Postoperative Pain Intensity Assessment: A Comparison of Four Scales in Chinese Adults

OBJECTIVE: To determine the psychometric properties and applicability of four pain scales in Chinese postoperative adults. DESIGN: A prospective clinical study. SETTING: A university-affiliated hospital. PATIENTS: In total, 173 Chinese patients (age range 18-78 years) undergoing scheduled surgery. INTERVENTIONS: Recalled pain and anticipated postoperative pain intensity were rated preoperatively with a visual analog scale (VAS), a numeric rating scale (NRS), a verbal descriptor scale (VDS), and the Faces Pain Scale Revised (FPS-R). From the day of surgery to the sixth postoperative day, patients were interviewed for the scores of current operative pain intensity and the worst, least, and average pain on that day. On the sixth postoperative day, retrospective ratings over the 7 days were also obtained and tool preferences were investigated. OUTCOME MEASURES: Scale reliability was evaluated using intraclass correlation coefficients (ICCs). Scale validity was assessed by correlations between scales, analysis of variance with repeated measures, and the sensitivity of the scales to interventions. Chi-square tests were used to investigate if error rate and preference rate were related to gender, age, and educational level. RESULTS: All four pain intensity scales had good reliability and validity when used with Chinese adults. The ICCs of the four scales across current, worst, least, and average pain on each postoperative day were consistently high (0.673-0.825), and all scales at each rating were strongly correlated (r = 0.71-0.99). Analysis of variance with repeated measures revealed significant decreases in scores associated with postoperative days, and all four scales were sensitive in evaluating analgesic efficacy. Both the VDS and the FPS-R had low error rates. Nearly half of the participants (48.1%) preferred the FPS-R, followed by the NRS (24.4%), the VDS (23.1%), and the VAS (4.4%); however, no significant differences were noted in terms of gender, age, and educational level. CONCLUSIONS: These findings demonstrate that although all four scales can be options for Chinese adults to report pain intensity, the FPS-R appears to be the best one. Providing tool options to address individual needs or preferences is suggested.